Impact of Eliminating Postprocedural Antibiotic Prophylaxis in Patients without Biliary Instrumentation or Bypass Undergoing Hepatic Artery Embolization for Hepatic Malignancies

Clinical question
To assess the infection rate after eliminating postprocedural antibiotics in patients undergoing hepatic artery embolization (HAE) for primary and secondary hepatic malignancies.

Take away point
Eliminating postprocedural antibiotics in patients undergoing HAE did not lead to an increase in infectious complications.

Reference
Impact of Eliminating Postprocedural Antibiotic Prophylaxis in Patients without Biliary Instrumentation or Bypass Undergoing Hepatic Artery Embolization for Hepatic Malignancies. Seo, Susan K. et al. Journal of Vascular and Interventional Radiology, Volume 30, Issue 12, 1895 - 1900

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Study design 

Retrospective cohort study of hepatic artery embolization patients who received either pre and postprocedural antibiotics or only preprocedural antibiotics.

Funding Source 
Partially funded through the US National Institutes of Health/National Cancer Center

Setting
Memorial Sloan Kettering Cancer Center, New York

Table 2. Comparison of outcomes for Adult Patients without Prior Biliary Instrumentation or Bypass undergoing HAE.

Summary

The authors performed a retrospective cohort study to compare infectious complications in hepatic artery embolization (HAE) patients that either received either pre- and post-procedure antibiotic prophylaxis or only pre-procedure antibiotic prophylaxis. Only patients without a history of prior biliary instrumentation or bypass were included. Patients that also received ablation or selective internal radiation treatment (SIRT) were included.

Group A comprised of 150 patients who underwent 204 HAE procedures and received pre- and post-procedure antibiotic prophylaxis. Group B comprised of 171 patients who underwent 204 HAE procedures and received only pre-procedure antibiotic prophylaxis. The retrospective cohorts were chosen based on consecutive cases performed a year before and a year after the guidelines at the author’s institution were changed to no longer recommend post-procedure antibiotic prophylaxis.

The pre-procedure antibiotic prophylaxis regimen was 1g of cefazolin iv pre-procedure. Patients with a severe penicillin allergy received clindamycin (900 mg iv for 1 dose pre-procedure) and gentamicin (1 dose 1.5 mg/kg iv pre-procedure). In the group receiving post-procedure prophylaxis, the regimen was either 1g cefazolin every 8 hours post-procedure for 3 doses or clindamycin (900 mg iv q8H for 3 doses) plus gentamycin (1.5 mg/kg q8H post-procedure for 3 doses).

The primary outcome was any infection requiring antimicrobial treatment within 30 days of hepatic artery embolization. In the comparison of HAE patients with or without ablation or SIRT, with a competent sphincter of Oddi, receiving both pre- and post-procedure antibiotic prophylaxis and only pre-procedure antibiotic prophylaxis: No significant difference was identified in 30-day infection rates. No significant difference was identified in the average time to postprocedural imaging or in the proportion of patients with liver imaging within 14 days of the procedure. No significant difference was found in unplanned readmissions within 30 days or in 30-day all-cause mortality. Elimination of post-procedure antibiotics also led to better guideline adherence within the author’s institution.

Commentary

The authors evaluated 321 patients who underwent 425 hepatic artery embolization procedures and received either pre- and post-procedure antibiotic prophylaxis or only pre-procedure antibiotic prophylaxis. No significant difference was seen in infectious complications or any of the other endpoints between the two groups. While this study is limited by its retrospective design and exclusion of patients with prior biliary intervention, these findings further confirm that a single pre-procedure prophylactic dose of either cefazolin or clindamycin plus gentamycin provides adequate antimicrobial coverage for these patients undergoing HAE and supports the 2018 SIR recommendations, and suggest the post-procedure antibiotic prophylaxis may be unnecessary.

Post author
Maxwell R. Cretcher, DO
Resident Physician, Integrated Interventional Radiology
Dotter Department of Interventional Radiology
Oregon Health & Science University

Transarterial Chemoembolization Followed by Radiofrequency Ablation for Hepatocellular Carcinoma: Impact of the Time Interval between the Two Treatments on Outcome

Clinical question
Does the efficacy of radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) differ within or beyond 30 days after transarterial chemoembolization (TACE)?

Take away point
RF ablation within 30 days after TACE was more effective for treatment of recurrent HCC than delayed ablation.

Reference
Liu, D. et al. Transarterial Chemoembolization Followed by Radiofrequency Ablation for Hepatocellular Carcinoma: Impact of the Time Interval between the Two Treatments on Outcome. J. Vasc. Interv. Radiol. 30, 1879–1886 (2019).

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Study design
Single-institution, retrospective study with 135 patients from 2007-2015 who presented with a recurrent HCC and subsequently underwent TACE plus RF ablation. Outcomes of interest included overall survival (OS), progression-free survival (PFS) and complete response (CR) rate.

Funding source
Science and Technology Development Special Fund of Guangdong Province grant 2017A020215011 and National Natural Science Foundation Key Program grant K0109003

Setting
The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China

Summary

This study reviewed 135 patients between 2007 and 2015 with either a solitary tumor > 3 cm or multiple tumors < 5 cm of recurrent HCC. Inclusion criteria, among others, comprised of first intrahepatic HCC recurrence after curative treatment (resection or ablation), no evidence of invasion/metastatic disease, and Child-Pugh classes A-B.

Sixty-two patients underwent TACE followed by sequential RF ablation within 30 days and 73 patients underwent RF ablation more than 30 days following TACE. Superselective conventional TACE was performed by the same interventional radiologist utilizing a mixture of lipiodol and epirubicin followed by gelatin sponge particle embolization. RF ablation was performed with the Cool-tip electrode [Valleylab; Medtronic, Fridely, Minnesota] with 2-3 electrodes used for a safety margin > 5 mm with guidance of contrast enhanced ultrasound.

Follow up consisted of contrast-enhanced cross-sectional imaging. Tumor response was assessed by the Modified Response Evaluation Criteria in Solid Tumor guidelines. Overall survival (OS) and progression-free survival (PFS) were calculated from the day of RF ablation.

The median OS was 49.8 months for the sequential group and 31.0 months for the delayed group (P = 0.002). Median PFS was 38.0 months for the sequential group and 11.6 months for the delayed group (P = 0.021). Subgroup analysis showed that patients with multiple tumors or a single tumor > 5 cm had significant longer OS and PFS when RF ablation was performed sequentially. There was no significant difference among patients with solitary 3 to 5 cm tumors when RF ablation was performed within or after 30 days of TACE. Complete tumor response rates were significantly better for the sequential group compared to the delayed group (P = 0.035). Multivariate analysis showed predictors of OS and PFS included maximum tumor size and number of tumors.

Commentary

Combination therapy for HCC with TACE followed by thermal ablation is frequently utilized to prevent recurrence. However, there is little knowledge regarding the optimal time interval between TACE and ablation. This retrospective study supports efficacy of early ablation within 30 days after TACE for in the treatment of large (> 5 cm) or multiple recurrent HCCs. These benefits were not seen for solitary medium sized tumors. Although the authors took care to account for operator variability with TACE, technical variability, management of multiple tumors and timing of repeat TACE can vary significantly among unique patients situations. While early ablation is preferred and encouraged after TACE, addition prospective randomized clinical trials may be beneficial, especially for solitary medium sized tumors.

Post author

Teodora Bochnakova MD
Assistant Professor
Department of Interventional Radiology
Oregon Health and Science University, Portland, OR
@T_bochnakova

Radiofrequency Ablation Duration per Tumor Volume May Correlate with Overall Survival in Solitary Hepatocellular Carcinoma Patients Treated with Radiofrequency Ablation Plus Lyso-Thermosensitive Liposomal Doxorubicin

Clinical question
Does burn time per tumor volume (BPV) in radiofrequency (RF) ablation and lyso-thermosensitive liposomal doxorubicin (LTLD) combination therapy for solitary hepatocellular carcinoma (HCC) correlate with treatment outcomes?

Takeaway point
Overall survival (OS) benefits were correlated with higher BPV in the RF ablation + LTLD combination compared to RF ablation alone in this retrospective post hoc analysis.

Reference
Radiofrequency Ablation Duration per Tumor Volume May Correlate with Overall Survival in Solitary Hepatocellular Carcinoma Patients Treated with Radiofrequency Ablation Plus Lyso-Thermosensitive Liposomal Doxorubicin, Volume 30, Issue 12, 1908-1914.

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Study design
Post hoc analysis of the double-blind, randomized controlled phase III HEAT study of RF ablation only versus RF ablation + LTLD in patients with HCCs 3-7 cm in diameter.

Funding Source
Intramural Research Program of the National Institutes of Health and the National Institutes of Health Center for Interventional Oncology (grants ZID# BC011242-9 and CL040015-9). The National Institutes of Health has a Cooperative Research and Development Agreement with Celsion Corporation (Lawrenceville, New Jersey).

Setting
NIH, United States of America.






Figure 2. Hazard ratio versus BPV cutoff. As patients with smaller values of BPV were excluded, the hazard ratio decreased, representing improved benefit for patients receiving RF ablation + LTLD compared with patients receiving RF ablation only. When patients with < 2 min/mL BPV were excluded, the hazard ratio was 0.7, which meant survival of patients receiving RF ablation + LTLD improved 42.8% compared with patients receiving RF ablation only. With exclusion of patients with < 3.4 min/mL BPV, the hazard ratio and survival improvement for patients receiving RF ablation + LTLD became 0.5 and 100%, respectively, compared with patients receiving RF ablation only.

Summary

Radiofrequency (RF) ablation, despite its widely adopted and successful treatment of hepatocellular carcinoma (HCC), has limited results for tumors > 3 cm. Alternative treatment methods, such as the synergistic combination of RF ablation and lyso-thermosensitive liposoam ldoxorubicin (LTLD), are in development. Although the phase III HEAT study did not demonstrate significant difference in progression-free survival (PFS) and overall survival (OS) between RF ablation only and RF ablation + LTLD, initial post hoc subgroup analysis in patients with > 45 minutes dwell time demonstrated improved OS of patients receiving RF ablation + LTLD compared to RF ablation only. Based on the LTLD formulation and pharmacokinetic modeling, it was hypothesized that RF ablation duration with respect to tumor volume would contribute significantly to treatment outcomes of RF ablation + LTLD in HCC.

HEAT study data was analyzed retrospectively. Original data was a double-blind, randomized controlled study with 701 patients of HCC between 3 cm and 7 cm distributed between RF ablation only and RF ablation + LTLD. Only patients with solitary tumors were further analyzed (n = 210 patients who received RF ablation only; n=227 patients who received RF ablation + LTLD). Hazard ratios were calculated with incremental threshold values of BPV. A univariate and multivariate Cox proportional hazard model was used for analysis.

No significant difference was found in terms of tumor volume, average burn times, or BPVs between the two treatment arms. Multiple covariate Cox survival analysis demonstrated BPV as a significant effect modifier, with each 1 min/mL increase in BPV contributing to an increase of 17.6% in overall survival in the RF ablation + LTLD arm compared to RF ablation alone. Univariate Cox survival analysis with incremental BPV cutoff values demonstrated gradually decreasing hazard ratios, signifying more pronounced effects of BPV on OS with higher threshold of BPV. Independently performed univariate Cox analysis within each treatment arm confirmed significant effects of BPV on OS in the RF ablation + LTLD arm; but not on PFS, nor in the RF ablation only arm. Feasibility analysis demonstrated that almost 80% of all examined solitary tumors could have been treated with a BPV of 2 min/mL if available burn time was 100 minutes.

Commentary

The authors in this study have demonstrated a potentially significant effect of BPV on the treatment outcomes of RF ablation + LTLD in solitary HCC between 3 cm and 7 cm through a post hoc analysis of the phase III HEAT study data. Results suggested a critical role of adequate burn time in RF ablation + LTLD treatment and BPV as a normalization/stratification metric. This study has its limitations given its retrospective post hoc nature as ablation time and other important variables were not included in the original analysis plan. HCCs with significant tumor volumes (7 cm tumor would equate to an ablation time of 360 minutes with a BPV of 2 min/mL) were likely receiving disproportionately lower BPVs. Therefore, the effects of higher BPVs on overall survival could not be safely separated from the inherent survival benefit of having a smaller HCC. However, the call for a more standardized determination of RF ablation time, especially in the RF ablation + LTLD combination regimen given its preclinical mechanistic data, should not be understated. Future prospective studies should be conducted to further evaluate the effects of ablation time in RF ablation + LTLD treatment for HCC and the potential of using BPV as a standardization metric.


Post author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-3
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute
@NingchengLi

A Descriptive Revenue Analysis of a Wound-center IR Collaboration To Treat Lower Extremity Venous Ulcers

Clinical question
How much revenue will be created by treating patients with venous leg ulcers in a joint collaboration between a wound care center and IR?

Take-away point
This joint venture between IR and wound care clinic generated revenue not only through procedures but also E&M, and imaging.

Reference

Ruohoniemi, David M. et al. A Descriptive Revenue Analysis of a Wound-Center IR Collaboration to Treat Lower Extremity Venous Ulcers. Journal of Vascular and Interventional Radiology, Volume 30, Issue 12, 1988 - 1993.

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Study design
Retrospective review of 36 venous ulcer patients

Funding source
None

Setting
Academic center, New York University School of Medicine





Figure 3. Relative wRVU contribution to total wRVU by category. (b) Relative revenue contribution by category. wRVU=workrelative value units.

Summary

Treatment of venous leg ulcers (VLU) requires a collaborative effort with a wound care center. The authors studied the revenue generated by developing a collaborative effort with the wound care center. Patients referred to IR were patients with previous stents, filters or what was considered “more difficult venous disease”. Patients were initially evaluated in a dedicated outpatient facility. Follow up was usually at 3 and 6 months, at which time further intervention or imaging was considered.

36 patients were included in the study, 15 patients underwent (16 procedures), 21 were evaluated but did not undergo an intervention. Sources of revenue included E&M visits (initial evaluation and follow up, diagnostic imaging (before and after procedure) and procedures. CPT codes were used to account for E&M visits, diagnostic studies and procedures. The professional component (wRVUs) was calculated based on the E&M visits, diagnostic imaging and procerus.

The authors report 70 total clinic visits (36 initial, 34 follow up) and 3.6 new consultations per month. 31 pre-procedural imaging studies were ordered and procedural patients required 11 post-procedure studies. The total wRVU generated from this venture was 518.15, 24% wRVUS were due to E&M, 10% from diagnostic studies and 66% from procedures. 86% of wRVUs were due to procedure patients. This translated to a total revenue of $37,522 over 10 months, 58% was due to procedures, 23% to E&M and 28% to diagnostic imaging. Intervention patents accounted for 80% of the revenue, and on average the individual patient revenue was $624 (range $110-$3,077).

The findings of the study support the concept that clinical involvement is not only good for patient care, but can also result in revenue for an IR practice. The authors use several examples to show how E&M codes provide significant revenue to other specialties (20% of revenue for vascular surgery and 40% for cardiology). The authors highlight that the revenue was derived from CMS rates and therefore it underestimates revenue by not taking into account private payers. The study also references data from an IVC filter clinic that generated $712 per patient, which was more than the average revenue per patient in the joint wound care clinic collaboration ($624), but less than the median intervention patient revenue ($1,931) and less than the pathway per patient revenue ($1,042). Overall an IVC filter clinic will lead to $22,775 over 10 months (compared to the $35,000 in the joint venture).

The authors identify that this study is limited by data from a single tertiary center, as well as lack of data for actual collections and charges, technical procedural revenue and hospital procedural revenue.

In conclusion, the authors find that a joint wound care-IR collaboration in the care of VLU patients may lead to substantial revenue from not only procedures but also E&M and diagnostic imaging.

Commentary

The authors provide more evidence that IR clinic and IR clinical involvement, is not only good medical practice, but may also become an important source of revenue. The authors provide examples on how similar specialties (Vascular surgery and Cardiology) derive significant revenue from E&M codes. It is clear that patients that undergo procedures, lead to a higher revenue, but the revenue generated from non-procedure patients is not negligible (20% of total revenue). Joint ventures with practices that have patients in common (wound clinic, podiatry) will lead not only to better clinical care and better outcomes, but potentially more referrals as well as creating other collaborative efforts (diabetic foot wounds, critical limb ischemia, etc).

Post author
Carlos J. Guevara, MD, FSIR
Assistant Professor of Radiology and Surgery
Division of Interventional Radiology
Mallinckrodt Institute of Radiology, St Louis, MO
@CarlosGuevaraIR

Endovascular Treatment of Complex Aneurysms with the Use of Covera Stent Grafts

Endovascular Treatment of Complex Aneurysms with the Use of Covera Stent Grafts 

Clinical Question
To characterize the short-term results of the Covera stent for the reconstruction of target vessels in complex aneurysms and assess the safety and efficacy of this stent.

Take-away Point
The Covera self-expanding stent offers good short term patency in chimney, branched, and fenestrated EVAR procedures.

Reference
Caradu C, Dubourg A, Colacchip E, Midy D, Bérard X, Ducasse E. (2019). Endovascular Treatment of Complex Aneurysms with the Use of Covera Stent Grafts. J Vasc Interv Rad, 30:1942-1948. doi:10.1016/j.jvir.2019.05.004

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Study Design
Nonrandomized, monocentric single-arm evaluation study

Funding Source
None

Setting

Dept of Vascular Surgery, Université de Bordeaux, France; Dept of Vascular Surgery, University Hospital of Poitiers, France; University Hospital of Padova, Italy




Figure 3. (a) Preoperative CT angiogram of an 84-year-old male patient showing a 60-mm type 3 thoracoabdominal aneurysm treated by using (b) a sandwich technique, with covered chimneys constructed using a self-expanding covered stent for the celiac trunk, the superior mesenteric artery, and both renal arteries. (c) The contrast-enhanced CT scan shows the positioning of the 4 self-expanding covered stents positioned between the 2 thoracic devices. (d) 3D reconstruction confirms the positioning of the devices and the preserved patency of the target arteries.

Summary

This single-center study assesses the safety and efficacy of the new Covera self-expanding stent for the use of chimey EVAR, branched EVAR (B-EVAR) and fenestrated EVAR (F-EVAR). It is a retrospective review of 17 patients treating 51 arteries (2.8 ± 1 per patient); 25 arteries were preserved using the Covera stent. Breakdown includes EVAR with hypogastric preservation (11.8%), B-EVAR (29.4%), F-EVAR (17.6%), chimney plus F-EVAR (11.8%) and chimney EVAR (29.4 %). This stentgraft employs a new delivery system minimizing foreshortening which may potentially lead to improved device placement accuracy. The stent has a nitinol structure lending itself to high flexibility and kink resistance, ideal for sharp angulations.

Intraoperative aneurysm occlusion was successful in 82.4% of patients; 2 gutter leaks, 1 type I endoleak, 6 type 2 endoleaks and 1 type 3 endoleak. Over the 10 ± 5-month observation period in this study, there was no evidence of target vessel occlusion. Two secondary procedures were required to address endoleak: a gutter endoleak and a type 3 endoleak in a fenestrated device.

Commentary 

The Covera stent is a new device on the market which offers alternative stent options to the Viabahn or VBX for chimney, fenestrated or branched EVARs. This retrospective study demonstrates similar success rates comparable to those in the reported literature. The flexible and kink-resistant delivery system makes this stent ideal for the extremely tortuous aorta or iliac system. While the study is limited in nature give the small sample size, retrospective nature, and short term follow-up, it does present promising results on the use of the Covera stent.

Post Author
Nicole A. Keefe, MD
Fellow, Interventional Radiology
Department of Radiology and Medical Imaging
University of Virginia
@NikkiKeefe